Search

WO-2026095660-A1 - POSITIVE ELECTRODE ACTIVE MATERIAL FOR SECONDARY BATTERY

WO2026095660A1WO 2026095660 A1WO2026095660 A1WO 2026095660A1WO-2026095660-A1

Abstract

A positive electrode active material according to one aspect of the present invention comprises a lithium composite oxide containing nickel (Ni), and comprises a coating material containing cobalt (Co) and boron (B), wherein the occupancy of Ni inserted into the Li 3a site of the positive electrode active material based on Rietveld analysis by X-ray diffraction may be 1.4% or less.

Inventors

  • OH, SEONGHO
  • LEE, SEULGI
  • BAE, JIN HO
  • LEE, DONGGEUN
  • SHIN, Sehee

Assignees

  • 주식회사 에코프로비엠

Dates

Publication Date
20260507
Application Date
20251030
Priority Date
20241101

Claims (14)

  1. It includes a lithium composite oxide containing nickel (Ni), and A coating material comprising cobalt (Co) and boron (B), and From Rietveld analysis by X-ray diffraction, the nickel occupancy (Ni occupancy) inserted into the Li 3a sites of the cathode active material is 1.4% or less, Cathode active material.
  2. In Article 1, The a-axis length obtained from Rietveld analysis by X-ray diffraction is 2.8782 Å to 2.8795 Å, Cathode active material.
  3. In Article 1, In thermal analysis by differential scanning calorimetry (DSC), the temperature at which the peak of maximum heat flow appears is between 218°C and 280°C, Cathode active material.
  4. In Article 1, In thermal analysis by differential scanning calorimetry (DSC), the maximum heat flow at the temperature where the peak of maximum heat flow appears is 1000 J/g or less, Cathode active material.
  5. In Article 1, In thermogravimetric analysis (TGA), the temperature at which weight loss begins to appear is 215°C to 280°C, Cathode active material.
  6. In Article 1, In thermogravimetric analysis (TGA), the temperature at which the weight loss peak reaches its highest point is 225°C to 280°C, Cathode active material.
  7. In Article 1, The above coating material further comprises one or more selected from aluminum (Al) and zirconium (Zr), Cathode active material.
  8. In Article 1, The above coating material further comprises aluminum (Al) and zirconium (Zr), Cathode active material.
  9. In Article 1, The positive electrode active material particles included in the above positive electrode active material include a bulk region and a coating region including the coating material, and The above bulk region is doped with one or more selected from aluminum (Al), zirconium (Zr), and cobalt (Co). Cathode active material.
  10. In Article 9, The above bulk region is not doped with boron (B), Cathode active material.
  11. In Article 1, Based on the total amount of the above-mentioned cathode active material, boron (B) is included in an amount of 0.01 mol% to 3.0 mol%, Cathode active material.
  12. In Article 1, The average particle size (D50) of the positive active material particles included in the above positive active material is 2.0 μm to 6.0 μm, Cathode active material.
  13. In Article 1, The lithium composite oxide particles included in the above-mentioned cathode active material consist of a single particle, or 2 to 8 single particles contained in contact, Cathode active material.
  14. In the method for manufacturing a positive electrode active material according to claim 1, A step of preparing a lithium composite oxide by heat-treating a mixture containing a positive electrode active material precursor and a lithium-containing compound; A step of first coating the above-prepared lithium composite oxide with a first coating material comprising a cobalt (Co)-containing compound; and A step comprising: heat-treating the first coating material with a second coating material containing a boron (B)-containing compound at a temperature of 300°C to 400°C to perform a second coating; Method for manufacturing positive electrode active material.

Description

Cathode active material for secondary batteries The present invention relates to a positive electrode active material for a secondary battery comprising a lithium composite oxide containing nickel (Ni), and more specifically, to a positive electrode active material in which thermal stability, lifespan characteristics, and output characteristics are all improved when applied to a secondary battery by controlling the coating composition, coating method, bulk composition, etc., in a lithium composite oxide containing nickel (Ni) coated with cobalt (Co) and boron (B), thereby controlling the values regarding crystal structure and thermal stability. With the advancement of portable mobile electronic devices such as smartphones, MP3 players, and tablet PCs, the demand for rechargeable batteries capable of storing electrical energy is increasing explosively. In particular, the demand for lithium-ion batteries is rising due to the emergence of electric vehicles, medium-to-large energy storage systems, and portable devices requiring high energy density. As a lithium composite oxide included in the cathode active material, the material that has recently been receiving the most attention is lithium nickel (manganese/aluminum) cobalt oxide Li(Ni x Co y( Mn/Al) z )O 2 (where x, y, and z are the atomic fractions of independent oxide composition elements, 0<x≤1, 0<y≤1, 0<z≤1, and 0<x+y+z≤1). This cathode active material has the advantage of producing a high capacity because it is used at high voltage compared to LiCoO 2 , which has been actively researched and used as a cathode active material, and has the advantage of a low cost because the Co content is relatively low. However, these lithium composite oxides undergo volume changes due to the intercalation and deintercalation of lithium ions during charging and discharging. There are problems such as the primary particles of the lithium composite oxide rapidly changing in volume during charging and discharging, cracks occurring in the secondary particles due to repeated charging and discharging, or the collapse of the crystal structure or phase transition of the crystal structure. Meanwhile, lithium composite oxides containing nickel have a problem in that thermal stability decreases as the Ni content increases. In addition, lithium composite oxides containing nickel have a problem in that their lifespan characteristics at room temperature and high temperature deteriorate rapidly as the Ni content increases due to increased structural instability caused by Li/Ni cation mixing, physical disintegration of internal particles caused by microcracks, and intensified depletion of electrolyte. Figure 1 is an SEM image of the surface of a positive electrode active material particle according to one embodiment of the present invention. FIG. 2 is a differential scanning calorimetry (DSC) analysis graph of a positive electrode active material according to one embodiment of the present invention. FIG. 3 is a thermogravimetric analysis (TGA) graph of a cathode active material according to one embodiment of the present invention. Expressions such as "comprising" as used in this specification should be understood as open-ended terms implying the possibility of including other configurations. As used herein, "preferably" and "preferably" refer to embodiments of the invention that can provide certain advantages under certain conditions. However, it is not intended to exclude other embodiments from the scope of the invention. Furthermore, the singular form used in the specification and the appended claims may be intended to include the plural form unless specifically indicated otherwise in the context. That is, a technical feature of a single particle may mean a technical feature of multiple particles, or may be intended to mean an average technical feature of multiple particles. The numerical ranges used in this specification include lower and upper limits and all values within the range, increments logically derived from the form and width of the defined range, all of which are limited values, and all possible combinations of upper and lower limits of numerical ranges limited in different forms. Unless otherwise specifically defined in this specification, values outside the numerical range that may occur due to experimental error or rounding are also included in the defined numerical range. The meanings of '≤', 'greater than or equal to', or 'less than or equal to' as described in this specification may be replaced with the meanings of '<', 'greater than', or 'less than'. Meanwhile, the technical features described below relate to one embodiment that achieves the intended effect of the present invention described above. That is, the positive electrode active material according to one embodiment of the present invention includes the technical features according to one embodiment described below, thereby providing a positive electrode active material in which the values regarding crystal s